The invention generally relates to the handling of freight in combined overland and marine transportation and is specifically directed to freight container adapted to be mounted on highway truck-trailer chassis, railroad flat cars or the like and stowed aboard ship. Freight containers which are capable of being stacked in a superimposed relation are known in the prior art specifically to fill the hold and increase deck storage of large sea going vessels. Examples of such containers are disclosed by U.S. Pat. Nos. 3,044,653 and 3,085,703. Containers of this type are provided with heavy steel or aluminum castings at each of the four front corners of the container and rear corners of the container. Each corner of the container is provided with a corner post connected between associated pairs of upper and lower steel castings which comprise the load bearing members of the containers. Conventional openings in each of the steel castings facilitate the interlocking of the container with suitable lifting means for transferring the container from a land vehicle to a ship and vice versa, as well as to facilitate the positioning and securing together of containers in a stacked relation. The corner castings are so related to the corner post and to the top, side, and end walls that the container may be stacked one on another with all of the load taken by the corner castings and corner posts.
Another container for handling freight is shown by U.S. Pat. No. 3,646,609. This reference provides for the stacking of conventional containers of varied size in superimposed relation. The container is constructed with front and sidewalls formed of metal panels.
The disclosed prior art containers necessitate the use of a three dimensional box shaped structure of continuous framing for purposes of handling freight. Since the freight is of substantial weight and size, it requires a box shaped container of sufficient strength and rigidity. The prior art container is an independent free-standing structure which makes no use of the freight to contribute to the container framing or structure.
The conventional container chassis and chassis frame are of lengths greater than the container frame for freight handling and of widths equal to that of the container frame. Thus the shipping and loading of a fully assembled container chassis or frame is not easily accomplished unless the chassis frame is disassembled and packaged or otherwise shipped via general cargo ship and not onboard a standard container ship as containerized freight or alternatively transported on highway vehicles as containerized freight.
Off-shore manufacturers of chassis have for some time been exporting chassis from their countries by general cargo (bulk) ships to the United States and other territories. Of course this involves some freight charge, normally charged per cubic meter (CBM). For example, skeletal steel chassis frames shipped by general cargo vessel from Korea, landing on the west coast of the United States at most favorable special CBM rates cost approximately U.S. $150 per/unit minimum, and may be as high as U.S. $280/unit. Additional costs are involved for dockside handling, in-land transportation, cargo damage, etc. Moreover, the chassis are not shipped as fully assembled, requiring additional work to be performed in the U.S. at U.S. labor rates. More importantly, the largest market for chassis sales is the U.S. east coast, but the availability of general cargo ships for east coast discharge is limited, and transit times and freight rates are prohibitive.
By providing the chassis to the buyers, ship operators, as containerized freight, all of the forementioned costs can be defrayed. The container ship operator can reposition its chassis throughout the world as "non-revenue freight, company business".